diff --git a/src/pydna/sequence_picker.py b/src/pydna/sequence_picker.py
index 21b3f2aa..33d63215 100644
--- a/src/pydna/sequence_picker.py
+++ b/src/pydna/sequence_picker.py
@@ -18,7 +18,7 @@
 tool = "pydna"
 
 
-def genbank_accession(s: str):
+def genbank_accession(s: str) -> Dseqrecord:
     """docstring."""
     s = Dseqrecord(s)